Beta Canum Venaticorum (β Canum Venaticorum, abbreviated Beta CVn, β CVn), also named Chara , is a

G-type main-sequence star A G-type main-sequence star (Spectral type: G-V), also often, and imprecisely called a yellow dwarf, or G star, is a main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.9 to 1.1 solar masses and an effective temp ...

in the northern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

of Canes Venatici. At an apparent visual magnitude of 4.25, it is the second-brightest star in the constellation. Based upon an annual

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

shift of , this star is distant from the Sun. Along with the brighter star Cor Caroli, the pair form the "southern dog" in this constellation that represents

hunting dog A hunting dog is a canine that hunts with or for hunters. There are several different types of hunting dog developed for various tasks and purposes. The major categories of hunting dog include hounds, terriers, dachshunds, cur type dogs, and g ...

Nomenclature

''β Canum Venaticorum'' ( Latinised to ''Beta Canum Venaticorum'') is the star's

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...

. The traditional name ''Chara'' was originally applied to the "southern dog", but it later became used specifically to refer to Beta Canum Venaticorum. Chara ''(χαρά)'' means 'joy' in Greek. In 2016, the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Chara'' for this star. In

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of va ...

, (), meaning '' Imperial Guards'', refers to an asterism consisting of Beta Canum Venaticorum,

Alpha Canum Venaticorum Cor Caroli is a binary star designated Alpha Canum Venaticorum or α Canum Venaticorum. The International Astronomical Union uses the name "Cor Caroli" specifically for the brighter star of the binary. Alpha Canum Venaticorum is the bri ...

10 Canum Venaticorum 10 Canum Venaticorum is the Flamsteed designation for an ordinary star in the northern constellation of Canes Venatici. It has an apparent visual magnitude of 5.95, which, according to the Bortle scale, can be faintly seen with the naked e ...

, 6 Canum Venaticorum, 2 Canum Venaticorum, and

67 Ursae Majoris Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa ...

. Consequently, the Chinese name for Beta Canum Venaticorum itself is (, en, the Fourth Star of Imperial Guards.)香港太空館 - 研究資源 - 亮星中英對照表
, Hong Kong Space Museum. Accessed on line November 23, 2010.

Observations

Beta CVn has a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

of G0 V, and so is a

. Since 1943, the

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors i ...

of this star has served as one of the stable anchor points by which other stars are classified. The spectrum of this star shows a very weak emission line of singly

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...

ized calcium (Ca II) from the

chromosphere A chromosphere ("sphere of color") is the second layer of a star's atmosphere, located above the photosphere and below the solar transition region and corona. The term usually refers to the Sun's chromosphere, but not exclusively. In the Su ...

, making it a useful reference star for a reference spectrum to compare with other stars in a similar spectral category. (The Ca-II emission lines are readily accessible and can be used to measure the level of activity in a star's chromosphere.) Beta CVn is considered to be slightly metal-poor, which means it has a somewhat lower portion of elements heavier than

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...

when compared to the Sun. In terms of mass, age and evolutionary status, however, this star is very similar to the Sun. As a result, it has been called a solar analog. It is about 3% less massive than the Sun, with a radius 12% larger than the Sun's and 15% greater luminosity. The components of this star's space velocity are = . In the past it was suggested that it may be a

spectroscopic binary A binary star is a system of two star, stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separa ...

. However, further analysis of the data does not seem to bear that out. In addition, a 2005 search for a

brown dwarf Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...

in orbit around this star failed to discover any such companion, at least down to the sensitivity limit of the instrument used.

Habitability

In 2006, astronomer

Margaret Turnbull Margaret Carol "Maggie" Turnbull (born 1975) is an American astronomer and astrobiologist. She received her PhD in Astronomy from the University of Arizona in 2004. Turnbull is an authority on star systems which may have habitable planets, sol ...

labeled Beta CVn as the top stellar system candidate to search for

extraterrestrial life Extraterrestrial life, colloquially referred to as alien life, is life that may occur outside Earth and which did not originate on Earth. No extraterrestrial life has yet been conclusively detected, although efforts are underway. Such life might ...

forms. Because of its solar-type properties, astrobiologists have listed it among the most astrobiologically interesting stars within 10 parsecs of the Sun. However, as of 2009, this star is not known to host planets.

References

External links

* * {{DEFAULTSORT:Beta Canum Venaticorum Canes Venatici Canum Venaticorum, Beta G-type main-sequence stars Canum Venaticorum, Beta Chara Canum_Venaticorum, 08 061317 109358 4785 Durchmusterung objects

Nomenclature

Observations

Habitability

See also

References

External links